Two-dimensional DNA typing

DNA typing based on gel electrophoretic separation of DNA fragments, followed by hybridization analysis, has become an important analytical tool in areas ranging from forensic science to population biology. This approach can be extended by combining size separation with sequence-specific separation in denaturing gradient gels; this creates a high resolution two-dimensional pattern. The high information content of this system means that very closely related individuals (even monozygotic twins) can be distinguished and that the genetic events associated with development or cancer, for instance, can be followed. Ultimately, 2-D DNA typing could lead to computerized matching of a single individual's genome to a database of genetic markers.